I just finished printing and installing a weighted backplate I found on Thingiverse.

https://www.thingiverse.com/thing:7135539

I used tungsten powder and capped it off with some epoxy to seal it in. My TX22 with an FRT now runs flawlessly suppressed with my Mask HD. The only ammo I’ve tested so far is Thunderbolts, but I plan on trying out some subsonic as well.